syzbot

loop2: detected capacity change from 0 to 128
EXT4-fs (loop2): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none.
ext4 filesystem being mounted at /154/file1 supports timestamps until 2038-01-19 (0x7fffffff)
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
'}--!/25293 is trying to acquire lock:
ffff888023e6c608 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
ffff888023e6c608 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1755 [inline]
ffff888023e6c608 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x2bf/0xea0 fs/ext4/inode.c:215

but task is already holding lock:
ffff88802d656c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1780 [inline]
ffff88802d656c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x321/0x1080 fs/ext4/migrate.c:438

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51
       ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline]
       ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2808
       do_writepages+0x3b3/0x630 mm/page-writeback.c:2575
       __writeback_single_inode+0x153/0xec0 fs/fs-writeback.c:1635
       writeback_single_inode+0x21f/0x760 fs/fs-writeback.c:1756
       write_inode_now+0x183/0x210 fs/fs-writeback.c:2808
       iput_final fs/inode.c:1807 [inline]
       iput+0x5ae/0x920 fs/inode.c:1846
       ext4_xattr_block_set+0x249e/0x32b0 fs/ext4/xattr.c:2146
       ext4_xattr_move_to_block fs/ext4/xattr.c:2664 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2739 [inline]
       ext4_expand_extra_isize_ea+0x12c5/0x1e80 fs/ext4/xattr.c:2827
       __ext4_expand_extra_isize+0x306/0x400 fs/ext4/inode.c:5990
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:6033 [inline]
       __ext4_mark_inode_dirty+0x45d/0x6e0 fs/ext4/inode.c:6111
       ext4_evict_inode+0x7f3/0xea0 fs/ext4/inode.c:254
       evict+0x4ca/0x8d0 fs/inode.c:705
       ext4_orphan_cleanup+0xbec/0x1420 fs/ext4/orphan.c:472
       __ext4_fill_super fs/ext4/super.c:5621 [inline]
       ext4_fill_super+0x5eea/0x67b0 fs/ext4/super.c:5744
       get_tree_bdev+0x3f3/0x520 fs/super.c:1591
       vfs_get_tree+0x8c/0x280 fs/super.c:1764
       do_new_mount+0x24b/0xa40 fs/namespace.c:3386
       do_mount fs/namespace.c:3726 [inline]
       __do_sys_mount fs/namespace.c:3935 [inline]
       __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (sb_internal){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
       percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51
       __sb_start_write include/linux/fs.h:1633 [inline]
       sb_start_intwrite include/linux/fs.h:1755 [inline]
       ext4_evict_inode+0x2bf/0xea0 fs/ext4/inode.c:215
       evict+0x4ca/0x8d0 fs/inode.c:705
       ext4_ext_migrate+0xd7a/0x1080 fs/ext4/migrate.c:588
       __ext4_ioctl fs/ext4/ioctl.c:1412 [inline]
       ext4_ioctl+0x1ee3/0x3b80 fs/ext4/ioctl.c:1630
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_writepages_rwsem);
                               lock(sb_internal);
                               lock(&sbi->s_writepages_rwsem);
  rlock(sb_internal);

 *** DEADLOCK ***

3 locks held by '}--!/25293:
 #0: ffff888023e6c418 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write_file+0x63/0x200 fs/namespace.c:456
 #1: ffff888077586810 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #1: ffff888077586810 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1411 [inline]
 #1: ffff888077586810 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_ioctl+0x1edb/0x3b80 fs/ext4/ioctl.c:1630
 #2: ffff88802d656c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1780 [inline]
 #2: ffff88802d656c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x321/0x1080 fs/ext4/migrate.c:438

stack backtrace:
CPU: 1 PID: 25293 Comm: '}--! Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51
 __sb_start_write include/linux/fs.h:1633 [inline]
 sb_start_intwrite include/linux/fs.h:1755 [inline]
 ext4_evict_inode+0x2bf/0xea0 fs/ext4/inode.c:215
 evict+0x4ca/0x8d0 fs/inode.c:705
 ext4_ext_migrate+0xd7a/0x1080 fs/ext4/migrate.c:588
 __ext4_ioctl fs/ext4/ioctl.c:1412 [inline]
 ext4_ioctl+0x1ee3/0x3b80 fs/ext4/ioctl.c:1630
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa3b179ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa3b2594028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa3b1a15fa0 RCX: 00007fa3b179ce59
RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000005
RBP: 00007fa3b1832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3b1a16038 R14: 00007fa3b1a15fa0 R15: 00007ffe5d7f2aa8
 </TASK>